Boy’s Brain Works Just Fine After a Large Piece Was Removed

(NEW SCIENTIST) 31 July 2018, By Alison George – A boy who had a large portion of his brain removed to relieve his severe epilepsy is still able to function normally, showing how adaptable our brains can be.

The boy started having seizures at the age of four. No treatments could stop his epilepsy, so as a last resort surgeons removed a third of his brain’s right hemisphere just before his seventh birthday. This “lobectomy” surgery removed his entire occipital lobe, which carries out visual processing, and most of his temporal lobe, which processes visual and auditory information.

Researchers wanted to find out how the boy’s brain would recover after losing one of its visual centres – we usually have two, one in each of the brain’s hemispheres. A key question was what would happen to the boy’s “higher order” visual capabilities, such as being able to recognise faces and objects – mainly the job of the right hemisphere.

By studying the boy’s brain and behaviour for three years following his surgery, the team could see which parts of his brain were able to recover. Remarkably, they found that his intellect, visual perception, and face and object recognition skills were all normal for his age.

Rearranged brain

The only thing the boy can’t do is see the whole visual field. “He is essentially blind to information on the left side of the world. Anything to the left of his nose is not transmitted to his brain, because the occipital lobe in his right hemisphere is missing and cannot receive this information,” says Marlene Behrmann of Carnegie Mellon University, Pennsylvania. It seems that humans need two hemispheres to have full 180 degree vision, she says.

While the boy’s ability to “see” with the right hand side of his brain never recovered, the team found that his left hemisphere reorganised itself to take over high-level tasks such as face and object recognition. This hemisphere is normally more involved in tasks like word recognition, such as knowing that a round green object you see is an apple.

“We saw a kind of jostling in the left hemisphere between regions engaged in word and face recognition, which resolved and settled into a new organisation,” says Behrmann.

These high-level abilities may have been able to recover because they were still developing when the boy had his lobectomy, says Behrmann. Other people who lose one of their visual systems may not fare as well, she warns.